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which of the statements is true? oa. as x approaches positive infinity,…

Question

which of the statements is true?
oa. as x approaches positive infinity, f(x) exceeds g(x) and h(x).
ob. as x approaches positive infinity, g(x) exceeds f(x) and h(x).
oc. as x approaches positive infinity, h(x) converges with g(x).
od. as x approaches positive infinity, h(x) exceeds f(x) and g(x).

Explanation:

Step1: Analyze the growth rate of linear, exponential and logarithmic functions

  • \(f(x)\) is a linear function (\(y = x - 1\)). The general form of a linear function is \(y=mx + b\) with a constant slope \(m\). As \(x\to+\infty\), \(y = mx + b\) grows at a constant rate.
  • \(g(x)\) is an exponential - like function (assuming \(g(x)=2^{x}\) based on its shape). The general form of an exponential function is \(y = a\cdot b^{x}+c\) (\(b> 1\)). As \(x\to+\infty\), \(y=a\cdot b^{x}+c\) (\(b > 1\)) grows much faster than a linear function. The growth rate of \(y=a\cdot b^{x}+c\) (\(b>1\)) is proportional to the function's current value.
  • \(h(x)\) is a logarithmic - like function (assuming \(h(x)=\log_{2}(x + 3)\) based on its shape). The general form of a logarithmic function is \(y=\log_{b}(x - h)+k\). As \(x\to+\infty\), \(y = \log_{b}(x - h)+k\) grows, but its growth rate \(\frac{dy}{dx}=\frac{1}{(x - h)\ln b}\) approaches \(0\).

Step2: Compare the functions as \(x\to+\infty\)

  • For a linear function \(y_1=mx + b\) (\(m>0\)), an exponential function \(y_2=a\cdot b^{x}+c\) (\(b > 1,a>0\)) and a logarithmic function \(y_3=\log_{d}(x - k)+l\) (\(d>1\)):
  • \(\lim_{x\to+\infty}\frac{y_1}{y_2}=\lim_{x\to+\infty}\frac{mx + b}{a\cdot b^{x}+c}\). Using L'Hopital's rule (for \(\frac{\infty}{\infty}\) form, if we consider the ratio of the derivatives), \(\lim_{x\to+\infty}\frac{m}{a\cdot b^{x}\ln b}=0\). So \(y_2\) (exponential - type function \(g(x)\)) grows faster than \(y_1\) (linear function \(f(x)\)).
  • \(\lim_{x\to+\infty}\frac{y_3}{y_2}=\lim_{x\to+\infty}\frac{\log_{d}(x - k)+l}{a\cdot b^{x}+c}\). Since the derivative of \(\log_{d}(x - k)+l\) is \(\frac{1}{(x - k)\ln d}\) and the derivative of \(a\cdot b^{x}+c\) is \(a\cdot b^{x}\ln b\), \(\lim_{x\to+\infty}\frac{\frac{1}{(x - k)\ln d}}{a\cdot b^{x}\ln b}=0\). So \(y_2\) (exponential - type function \(g(x)\)) grows faster than \(y_3\) (logarithmic - type function \(h(x)\)).

Answer:

B. As \(x\) approaches positive infinity, \(g(x)\) exceeds \(f(x)\) and \(h(x)\)